Safety Fears Up In The Air
Questions like these are concentrating the minds of all sections of the air industry from airlines to aircraft manufacturers, and from safety committees to regulatory authorities.
Modern aircraft increasingly rely on electronic equipment for their navigation and communication systems, and a growing number of aeroplanes are operated by fly-by-wire technology, which uses electronics systems to control flight operations. Many electronic devices, including portable computers, personal stereos and hand-held computer game consoles, can produce spurious electromagnetic emissions. Some fear that in certain circumstances, these could affect an aircrafts electronics systems and thus compromise air safety.
As yet, there is little clear-cut evidence to support this theory, but with safety a paramount concern of the air industry, some are urging greater caution.
Much of the evidence on the potential of electronic devices to cause interference is anecdotal. There have been a number of reported incidents where a pilot has noticed a sudden change in the aircrafts instrumentation such as a needle flicking or a compass swinging wildly. When the pilot has asked passengers to stop using their devices the instruments have returned to normal. But were they the cause or was it just coincidence?
There is a suggestion that some equipment might have caused interference, but no one has been able to replicate it. So theres a suspicion about portable electronic equipment, but no hard proof, says Richard Wright of the UK Civil Aviation Authority.
Aircraft manufacturers have also carried out exhaustive tests, but the results have been inconclusive at best. Airbus Industrie, the European aircraft manufacturer, believes the case not proven.
Bruce Donham, electromagnetic effects engineer at Boeing, the worlds largest commercial aircraft manufacturer, says, We have spent over 40 years trying to duplicate many of the reported effects, but despite using the same devices under the same aircraft conditions, we have not been able to demonstrate them.
Donham adds that during the manufacturing test stage, all aircraft electronics are subjected to electromagnetic emissions that are much higher than anything that could be produced by a portable device.
However, air regulatory authorities such as the CAA and the US Federal Aviation Authority have issued guidelines to airline operators, which state that such devices should not be used during critical stages of a flight, such as take-off and landing. However, airline operators can decide which are allowed during other parts of the flight.
Cellular phones are banned on all flights but this is because they disrupt the cellular network, not for safety reasons.
Many airlines offer in-flight telephones, but these use satellites or frequencies specially allocated for air to ground transmissions. Likewise, in-flight entertainment systems, such as personal video consoles, and special devices, such as heart pacemakers and hearing aids, produce little or no emissions and are not suspected of causing interference.
Airline operators are well aware of the popularity of personal devices. Many business passengers for example, like to do work on their portable computers during a flight, and some airlines are introducing power points for laptops in their premium class cabins. Little wonder that some feel that it would be a brave airline operator that banished portable computers from its flight cabins.
But some critics argue that considerations like this have caused airlines to interest the guidelines in an inconsistent manner. In 1992, RTCA, a private US aviation technology company, formerly known as the Radio Technical Commission for Aeronautics, formed a special committee to investigate the potential interference of electronic devices aboard aircraft.
The committee admits that it did not carry out exhaustive tests, but based its recommendations on evidence collected over several years. It found 137 cases of suspected interference. In about 46 cases, the interference disappeared when the devices were turned off, and in 10 cases, the interference returned when the device was switched back on. Its a very rare occurrence, but the risk is there, says committee chairman John Sheehan.
Among the recommendations are that all devices designed to transmit radio frequencies, such as remote-controlled toys and two-way pagers, should be prohibited at all times, unless they have passed safety checks. The committee also wants the US government and air industry to consider fitting electromagnetic emission detectors inside air-craft cabins.
Finbarr OConnor, one of the committees members, wanted even stronger action. If it were up to me, I would shut PEDs down, period. I would feel better if they were not allowed in the passenger compartment at all. The potential for them to be turned on accidentally is high, he says.
But some believe that much of the concern is exaggerated. The pilots and flight attendants dont want to die, so if there was a real risk, the devices would be banned, says David Learnmount, operation and safety editor of Flight International magazine. And all aircraft have back up systems. Asking people not to use portable electronic equipment during take off is like the old superstition of touching wood to ward off evil spirits, he adds.
Sheehan says the committee would like to see a public education programme on the potential hazards of electronic devices. Youre going to see new kinds of PEDs being taken on board aircraft, such as personal communication devices. Some of these are subtle transmitters, which transmit even when they are switched off. People need to understand the importance of not using PEDs during critical flight stages.
Sheehan is also critical of FAA guidelines, which he says are too flexible. The air safety instructions you get before take-off are standardised. So why cant the same be done for PEDs? Different airlines have different rules. Air France and Japan Airlines, for example, allow portable CD players to be used on their aircraft, but Lufthansa, the German national carrier, has banned them. We have had cases of CD players causing interference and so we prohibit them, it says. Lufthansa also bans portable computers that use a printer, cordless mouse or CD-Rom drive, because they transmit data to the PC, but other airlines allow them.
JAL recently added digital cameras, which record images on a chip, to its list of prohibited devices. The company is also running a three-month campaign which gives passengers the chance to win Tamagotchi, a virtual-reality electronic pet that is Japans best-selling novelty toy. JAL says the pet is safe to use on board, although owners are asked not to play with it during take-off and landing.
George Cole